The present invention relates to improved detergent and cleaning products containing particular types of alkylarylsulfonate surfactants. More particularly, these alkylarylsulfonates have chemical compositions which differ both from the highly branched nonbiodegradable or xe2x80x9chardxe2x80x9d alkylbenzenesulfonates still commercially available in certain countries; and which differ also from the so-called linear alkylbenzenesulfonates which have replaced them in most geographies, including the most recently introduced so-called xe2x80x9chigh 2-phenylxe2x80x9d types. Moreover the selected surfactants are formulated into new detergent compositions by combination with particular detergent adjuncts. The compositions are useful for cleaning a wide variety of substrates.
Historically, highly branched alkylbenzenesulfonate surfactants, such as those based on tetrapropylene (known as xe2x80x9cABSxe2x80x9d) were used in detergents. However, these were found to be very poorly biodegradable. A long period followed of improving manufacturing processes for alkylbenzenesulfonates, making them as linear as practically possible (xe2x80x9cLASxe2x80x9d). The overwhelming part of a large art of linear alkylbenzenesulfonate surfactant manufacture is directed to this objective. All relevant large-scale commercial alkylbenzenesulfonate processes in use today are directed to linear alkylbenzenesulfonates. However, linear alkylbenzenesulfonates are not without limitations; for example, they would be more desirable if improved for hard water and/or cold water cleaning properties. Thus, they can often fail to produce good cleaning results, for example when formulated with nonphosphate builders and/or when used in hard water areas.
As a result of the limitations of the alkylbenzenesulfonates, consumer cleaning formulations have often needed to include a higher level of cosurfactants, builders, and other additives than would have been needed given a superior alkylbenzenesulfonate.
Accordingly it would be very desirable to simplify detergent formulations and deliver both better performance and better value to the consumer. Moreover, in view of the very large tonnages of alkylbenzenesulfonate surfactants and detergent formulations used worldwide, even modest improvements in performance of the basic alkylbenzenesulfonate detergent could carry great weight.
To understand the art of making and use of sulfonated alkylaromatic detergents, one should appreciate that it has gone through many stages and includes (a) the early manufacture of highly branched nonbiodegradable LAS (ABS); (b) the development of processes such as HF or AlCl3 catalyzed process (note each process gives a different composition, e.g., HF/olefin giving lower 2-phenyl or classic AlCl3/chloroparaffin typically giving byproducts which though perhaps useful for solubility are undesirable for biodegradation); (c) the market switch to LAS in which a very high proportion of the alkyl is linear; (d) improvements, including so-called xe2x80x98high 2-phenylxe2x80x99 or DETAL processes (in fact not really xe2x80x9chighxe2x80x9d 2-phenyl owing to problems of solubility when the hydrophobe is too linear); and (e) recent improvements in the understanding of biodegradation.
The art of alkylbenzenesulfonate detergents is extraordinarily replete with references which teach both for and against almost every aspect of these compositions. For example, some of the art teaches toward high 2-phenyl LAS as desirable, while other art teaches in exactly the opposite direction. There are, moreover, many erroneous teachings and technical misconceptions about the mechanism of LAS operation under in-use conditions, particularly in the area of hardness tolerance. The large volume of such references debases the art as a whole and makes it difficult to select the useful teachings from the useless without large amounts of repeated experimentation. To further understand the state of the art, it should be appreciated that there has been not only a lack of clarity on which way to go to fix the unresolved problems of linear LAS, but also a range of misconceptions, not only in the understanding of biodegradation but also in basic mechanisms of operation of LAS in presence of hardness. According to the literature, and general practice, surfactants having alkali or alkaline earth salts that are relatively insoluble (their Na or Ca salts have relatively high Krafft temperature) are less desirable than those having alkali or alkaline earth salts which are relatively higher in solubility (Na or Ca salts have lower Krafft temperature). In the literature, LAS mixtures in the presence of free Ca or Mg hardness are said to precipitate. It is also known that the 2- or 3-phenyl or xe2x80x9cterminalxe2x80x9d isomers of LAS have higher Krafft temperatures than, say, 5- or 6-phenyl xe2x80x9cinternalxe2x80x9d isomers. Therefore, it would be expected that changing an LAS composition to increase the 2- and 3-phenyl isomer content would decrease the hardness tolerance and solubility: not a good thing. On the other hand it is also known that with built conditions under which both the 2- and 3-phenyl and internal-phenyl isomers at equal chain length can be soluble, the 2- and 3-phenyl isomers are more surface-active materials. Therefore, it would be expected that changing an LAS composition to increase the 2- and 3-phenyl isomer content may increase the cleaning performance. However, the unsolved problems with solubility, hardness tolerance, and low temperature performance still remain.
U.S. Pat. No. 5,026,933; U.S. Pat. No. 4,990,718; U.S. Pat. No. 4,301,316; U.S. Pat. No. 4,301,317; U.S. Pat. No. 4,855,527; U.S. Pat. No. 4,870,038; U.S. Pat. No. 2,477,382; EP 466,558, Jan. 15, 1992; EP 469,940, Jan. 5, 1992; FR 2,697,246, Apr. 29, 1994; SU 793,972, Jan. 7, 1981; U.S. Pat. No. 2,564,072; U.S. Pat. No. 3,196,174; U.S. Pat. No. 3,238,249; U.S. Pat. No. 3,355,484; U.S. Pat. No. 3,442,964; U.S. Pat. No. 3,492,364; U.S. Pat. No. 4,959,491; WO 88/07030, Sep. 25, 1990; U.S. Pat. No. 4,962,256, U.S. Pat. No. 5,196,624; U.S. Pat. No. 5,196,625; EP 364,012 B, Feb. 15, 1990; U.S. Pat. No. 3,312,745; U.S. Pat. No. 3,341,614; U.S. Pat. No. 3,442,965; U.S. Pat. No. 3,674,885; U.S. Pat. No. 4,447,664; U.S. Pat. No. 4,533,651; U.S. Pat. No. 4,587,374; U.S. Pat. No. 4,996,386; U.S. Pat. No. 5,210,060; U.S. Pat. No. 5,510,306; WO 95/17961, Jul. 6, 1995; WO 95/18084; U.S. Pat. Nos. 5,087,788; 5,625,105 and 4,973,788 are useful by way of background to the invention. The manufacture of alkylbenzenesulfonate surfactants has recently been reviewed. See Vol 56 in xe2x80x9cSurfactant Sciencexe2x80x9d series, Marcel Dekker, New York, 1996, including in particular Chapter 2 entitled xe2x80x9cAlkylarylsulfonates: History, Manufacture, Analysis and Environmental Propertiesxe2x80x9d, pages 39-108 which includes 297 literature references. Documents referenced herein are incorporated in their entirety.
It is an object to provide the improved surfactants and surfactant mixtures comprising the same. It is another object herein to provide improved detergent compositions comprising certain sulfonated alkylbenzenes. These and other objects of the present invention will be apparent from the description hereinafter.
The present invention has numerous advantages beyond satisfying one or more of the objects identified hereinabove, including but not limited to: superior cold-water solubility, for example for cold water laundering; superior hardness tolerance; and excellent detergency, especially under low-temperature wash conditions. Further, the invention is expected to provide reduced build-up of old fabric softener residues from fabrics being laundered, and improved removal of lipid or greasy soils from fabrics. Benefits are expected also in non-laundry cleaning applications, such as dish cleaning. The development offers substantial expected improvements in ease of manufacture of relatively high 2-phenylsulfonate compositions, improvements also in the ease of making and quality of the resulting detergent formulations; and attractive economic advantages.
The present invention is based on an unexpected discovery that there exist, in the middle ground between the old, highly branched, less biodegradable alkylbenzenesulfonates and the new linear types, certain alkylbenzenesulfonates which are both more highly performing than the latter and more biodegradable than the former.
The new alkylbenzenesulfonates are readily accessible by several of the hundreds of known alkylbenzenesulfonate manufacturing processes. For example, the use of certain dealuminized mordenites permits their convenient manufacture.
In accordance with a first aspect of present the invention a novel surfactant system is provided. This novel surfactant system comprises
at least two alkylarylsulfonate surfactants of the formula: 
xe2x80x83wherein:
L is an acyclic aliphatic hydrocarbyl of from 6 to 18 carbon atoms in total;
M is a cation or cation mixture and q is the valence thereof;
a and b are numbers selected such that said alkylarylsulfonate surfactant is electroneutral;
Rxe2x80x2 is selected from H and C1 to C3 alkyl;
Rxe2x80x3 is selected from H and C1 to C3 alkyl;
Rxe2x80x2xe2x80x3 is selected from H and C1 to C3 alkyl; both of Rxe2x80x2 and Rxe2x80x3 are nonterminally attached to L and at least one of Rxe2x80x2 and Rxe2x80x3 is C1 to C3 alkyl; and
A is aryl;
xe2x80x83wherein:
said alkylarylsulfonate surfactant system comprises two or more isomers with respect to positions of attachment of Rxe2x80x2, Rxe2x80x3 and A to L;
in at least about 60% of said composition, A is attached to L in the position which is selected from positions alpha- and beta- to either of the two terminal carbon atoms of L; and
xe2x80x83wherein further said alkylarylsulfonate surfactant system has at least one of the following properties:
said alkylarylsulfonate surfactant system has a ratio of nonquaternary to quaternary carbon atoms in L of at least about 5:1 by weight, when said quaternary carbon atoms are present; or
percentage biodegradation, as measured by the modified SCAS test, that exceeds tetra propylene benzene sulphonate.
More preferably, percentage biodegradation in absolute terms, is preferably at least about 60%, more preferably at least 70%, still more preferably at least 80% and most preferably at least 90%, as measured by the modified SCAS test (described herein after).
In the invention, the surfactant system will preferably comprise at least two, referably at least four, more preferably at least eight, even more preferably at least twelve, even more preferably still at least sixteen and most preferably at least twenty, isomers and/or homologs of alkyarylsulfonate surfactant of formula (I). xe2x80x9cIsomersxe2x80x9d, which are described herein after in more detail, include especially those compounds having different positions of attachment of the moieties Rxe2x80x2 and/or Rxe2x80x3 to the L moiety. xe2x80x9cHomologsxe2x80x9d vary in the number of carbon atoms contained in the sum of L, Rxe2x80x2 and Rxe2x80x3.
In accordance with a second aspect of present the invention, a novel cleaning composition is provided. This novel cleaning composition comprises from about 0.01% to about 99.99% by weight of the novel surfactant composition and from about 0.0001% to about 99.99% by weight of a cleaning additive.
The cleaning composition will preferably contain at least about 0.1%, more preferably at least about 0.5%, even more preferably still, at least about 1% by weight of said composition of the surfactant system. The cleaning composition will also preferably contain no more than about 80%, more preferably no more than about 60%, even more preferably, no more than about 40% by weight of said composition of the surfactant system.
The preferred cleaning composition embodiments also contain specific cleaning additives, defined hereafter.
All percentages, ratios and proportions herein are by weight, unless otherwise specified. All temperatures are in degrees Celsius (xc2x0 C.) unless otherwise specified. All documents cited are in relevant part, incorporated herein by reference.
The present in invention relates to novel surfactant compositions. It also relates to novel cleaning compositions containing the novel surfactant system.
The surfactant system comprises at least two alkylarylsulfonate surfactants of the formula: 
wherein M is a cation or cation mixture. Preferably, M is an alkali metal, an alkaline earth metal, ammonium, substituted ammonium or mixtures thereof, more preferably sodium, potassium, magnesium, calcium or mixtures thereof. The valence of said cation, q, is preferably 1 or 2. The numbers a and b are selected such that said composition is electroneutral; a and b are preferably 1 or 2, and 1, respectively.
A is selected from aryl. Preferably, Ar is benzene, toluene, xylene, naphthalene, and mixtures thereof, more preferably Ar is benzene or toluene, most preferably benzene.
Rxe2x80x2 is selected from H and C1 to C3 alkyl. Preferably, Rxe2x80x2 is H or C1 to C2 alkyl, more preferably, Rxe2x80x2 is methyl or ethyl, most preferably Rxe2x80x2 is methyl. Rxe2x80x3 is selected from H and C1 to C3 alkyl. Preferably, Rxe2x80x3 is H or C1 to C2 alkyl, more preferably, Rxe2x80x3 is H or methyl. Rxe2x80x2xe2x80x3 is selected from H and C1 to C3 alkyl. Preferably Rxe2x80x2xe2x80x3 is H or C1 to C2 alkyl, more preferably, Rxe2x80x2xe2x80x3 is H or methyl, most preferably Rxe2x80x2xe2x80x3 is H. Both of Rxe2x80x2 and Rxe2x80x3 are nonterminally attached to L. That is, R,xe2x80x2 and Rxe2x80x3 do not add to the overall chain length of L, but rather, are groups branching from L. Also, at least one of Rxe2x80x2 and Rxe2x80x3 is C1 to C3 alkyl. This limits L to a hydrocarbyl molecule with at least one alkyl branch.
L is an acyclic aliphatic hydrocarbyl of from 6 to 18, preferably from 9 to 14 (when only one methyl branching), carbon atoms in total. The preferred L is a moiety Rxe2x80x3xe2x80x3xe2x80x94C(xe2x88x92)H(CH2)vC(xe2x88x92)H(CH2)xC(xe2x88x92)H(CH2)yxe2x80x94CH3, which includes the Rxe2x80x3xe2x80x3, but not Rxe2x80x2, Rxe2x80x3 or the A moiety, in the formula (II) below 
wherein Rxe2x80x2, Rxe2x80x3, Rxe2x80x2xe2x80x3, A, M, q, a and b are hereinbefore defined. Rxe2x80x3xe2x80x3 is selected from H, or C1 to C4 alkyl.
Preferably Rxe2x80x3xe2x80x3 is H or C1 to C3 alkyl, more preferably Rxe2x80x3xe2x80x3 is H or C1 to C3 alkyl, most preferred, Rxe2x80x3xe2x80x3 is methyl or ethyl. The numbers of the methylene subunits, v, x and y are each independently integers from 0 to 10 provided that the total number of carbons attached to A is less than about 20. This number is inclusive of Rxe2x80x2, Rxe2x80x3, Rxe2x80x2xe2x80x3 and Rxe2x80x3xe2x80x3. Furthermore, when Rxe2x80x3xe2x80x3 is C1 the sum of v+x+y is at least 1; and when Rxe2x80x3xe2x80x3 is H the sum of v+x+y is at least 2. In the moiety Rxe2x80x3xe2x80x3xe2x80x94C(xe2x88x92)H(CH2)vC(xe2x88x92)H(CH2)xC(xe2x88x92)H(CH2)yxe2x80x94CH3 the three C(xe2x88x92) indicate the three carbon atoms where A, Rxe2x80x2 and Rxe2x80x3 are attached to the moiety.
The alkylarylsulfonate surfactant system comprises two or more isomers with respect to positions of attachment of Rxe2x80x2, Rxe2x80x3 and A to L. In at least about 60%, preferably, 70%, more preferably, 80%, of the surfactant composition, A is attached to L in the position which is selected from positions alpha- and beta- to either of the two terminal carbon atoms of L, preferably A is attached to L in position alpha to a terminal carbon atom of L. When L has its preferred structure, see formula (II) above, at least 40% of Rxe2x80x3xe2x80x3 will be either methyl or ethyl, so that A is alpha- or beta to the terminal carbon. The terms alpha- and beta- mean the carbon atoms which are one and two carbon atoms away, respectively, from the terminal carbon atoms. To better explain this, the structure below shows the two possible alpha-positions and the two possible beta-positions in a general linear hydrocarbon. 
Furthermore, in the first aspect of the invention, the alkylarylsulfonate surfactant system may have a ratio of nonquaternary to quaternary carbon atoms in L of at least about 5:1 by weight when said quaternary carbon atoms are present. Preferably the weight ratio of nonquaternary to quaternary carbon atoms in L is at least 10:1, more preferably at least 20:1, and most preferably at least 100:1. When L has its preferred structure, see formula (II) above, Rxe2x80x3xe2x80x3 can contain quaternary carbon atoms. That is, tertiary butane.
The alkylarylsulfonate surfactant system may have a percentage biodegradation, as measured by the modified SCAS test as described hereafter, that exceeds tetra propylene benzene sulphonate. Preferred alkylarylsulfonate surfactant systems according to the present invention have a percentage biodegradation of at least about 60%, preferably at least about 70%, more preferably at least about 80%, and most preferably at least about 90%.
The present invention is directed to an alkylarylsulfonate surfactant system containing at least two surfactants of the formula: 
wherein L, M, Rxe2x80x2, Rxe2x80x3, Rxe2x80x2xe2x80x3, q, a, b, A, are as hereinbefore defined. A preferred structure of the sum of L, Rxe2x80x2 and Rxe2x80x3 is: 
wherein Rxe2x80x3xe2x80x3, v, x and y are as hereinbefore defined. A is attached to this structure at the CH next to Rxe2x80x3xe2x80x3. Some possible surfactants present in the alkylaryl sulfonate system include: 
Structures (a) to (h) are only illustrative of some possible alkylarylsulfonate surfactants and are not intended to be limiting in the scope of the invention.
It is also preferred that the alkylarylsulfonate surfactants include at least two xe2x80x9cisomersxe2x80x9d selected from:
i) positional isomers based on positions of attachment of substituents Rxe2x80x2 and to L;
ii) stereoisomers based on chiral carbon atoms in L or its substituents;
iii) ortho-, meta- and para-isomers based on positions of attachment of substituents to Ar, when Ar is a substituted or unsubstituted benzene. This means that L can be ortho-, meta- or para- to A, L can be ortho-, meta- and para- to a substituent on A other than L (for example Rxe2x80x2xe2x80x3), or any other possible alternative.
An example of two type (i) isomers are structures are (a) and (c). The difference is that the methyl in (a) is attached at the 5-position, but in (c) the methyl is attached at the 7-position.
An example of two type (iii) isomers are structures are (l) and (m). The difference is that the sulfonate group in (l) is meta- to the hydrocarbyl moiety, but in (m) the sulfonate is ortho- to the hydrocarbyl moiety.
An example of two type (ii) isomers are structures are (c) and (d). The difference is that these isomers are stereoisomers, the chiral carbon being the 7th carbon atom in the hydrocarbyl moiety.